# Math Help - Chain rule problem

1. ## Chain rule problem

I'm trying to solve the following question, how would I go about solving this?

Let f (x, y) = e^(x+x^2 y ), x(t) = t cos(t), y(t) = sin(t).

Define the
composite function w(t) := f (x(t), y(t)). Find dw/dt(pi/2) using the chain rule.

2. See attachment

3. Hi, Thanks. I got as far as writing out the dw/dt (in your case df/dt), but I wasn't sure how to solve for pi/2. Could you please explain how you did that part? Thanks.

4. x= tcos(t) y= sin(t)

so when t= pi/2 x= 0 y = 1